What made 75-year-old June Hautot so excited that she called Andrew Lansley a liar and physically blocked his path to Monday's NHS summit at No 10 (pictured right)? What makes any normally well-behaved person do it? Anger, frustration, a feeling that the powerful aren't listening, not to mention a desire to subvert the proceedings and knock the powerful or the merely rich and famous off their stride.

In cricket they call it sledging - as in, "How's you wife and my kids?" (Rod Marsh, bowling) "The wife's fine but the kids are retarded" (Ian Botham, batting) and it's admired. In politics, where heckling used to be an art form (Heckler: "Rubbish!" Harold Wilson: "I'll come to your special interest next, sir"), it is feared. Hautot once shared a protestor's cell with Anne Scargill; nothing Lansley could have said would have persuaded her that he is not selling the NHS to Walmart. No more could Jack Straw have convinced Walter Wolfgang. When Wolfgang was ejected from a Labour conference in 2005 for heckling Straw (alas, he's deaf in one ear) with the word "Nonsense!", Wolfgang (then 82) got elected to the party executive as a reward. The elderly seem to have more confidence.

They also remember to vote.

Such events sometimes catch a mood or moment. Witness Gillian Duffy's mild remarks about immigration levels (no heckler she: Duffy spoke privately) which an open mic caught Gordon Brown calling "bigoted". Or Diana Gould, when she ambushed Margaret Thatcher with detailed challenges on the Falklands war in 1983.

As every heckler doesn't know, the term probably originated from the process by which Dundee textile workers "heckled" - teased or combed - raw flax from the plant. As voters Dundee folk were known for teasing answers out of VIPs that way too. The fact that heckling is a dying art form in an age of fake sincerity makes it more valuable than ever. Five key tips for successful heckling? 1) timing 2) brevity 3) wit 4) volume 5) a second quip in reserve in case the victim answers back.